U.S. patent number 4,572,888 [Application Number 06/563,484] was granted by the patent office on 1986-02-25 for photopolymerizable composition with adhesion improving additive.
This patent grant is currently assigned to Fuji Photo Film Co., Ltd.. Invention is credited to Masayuki Iwasaki, Minoru Maeda, Fumiaki Shinozaki.
United States Patent |
4,572,888 |
Maeda , et al. |
February 25, 1986 |
Photopolymerizable composition with adhesion improving additive
Abstract
A photopolymerizable composition which comprises as main
ingredients (1) a non-gaseous ethylenic unsaturated compound which
has at least two ethylenic unsaturated groups and forms a polymer
by the aid of a photopolymerization initiator, (2) a thermoplastic
organic polymer binder, (3) a photopolymerization initiator which
is activated by activating light, and (4) a derivative of a
thiohydrazide compound or at least one derivative of a carbothio
acid amide. This composition forms a photoresist for producing
printed circuit boards, printing plates, etc., by etching or
plating. The photoresist has superior adhesion with respect to the
base.
Inventors: |
Maeda; Minoru (Shizuoka,
JP), Iwasaki; Masayuki (Shizuoka, JP),
Shinozaki; Fumiaki (Shizuoka, JP) |
Assignee: |
Fuji Photo Film Co., Ltd.
(Kanagawa, JP)
|
Family
ID: |
26378769 |
Appl.
No.: |
06/563,484 |
Filed: |
December 20, 1983 |
Foreign Application Priority Data
|
|
|
|
|
Dec 20, 1982 [JP] |
|
|
57-223277 |
Mar 10, 1983 [JP] |
|
|
58-39399 |
|
Current U.S.
Class: |
430/288.1;
430/275.1; 522/72; 522/78 |
Current CPC
Class: |
C08F
2/50 (20130101); G03F 7/085 (20130101); H05K
3/0076 (20130101); H05K 2203/124 (20130101); H05K
3/064 (20130101); H05K 3/389 (20130101) |
Current International
Class: |
C08F
2/50 (20060101); C08F 2/46 (20060101); G03F
7/085 (20060101); H05K 3/00 (20060101); H05K
3/38 (20060101); H05K 3/06 (20060101); G03C
001/74 () |
Field of
Search: |
;430/281,288,919,921,275,227 ;204/159.18,159.24 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Brammer; Jack P.
Attorney, Agent or Firm: Sughrue, Mion, Zinn, Macpeak, and
Seas
Claims
What is claimed is:
1. A photopolymerizable composition which comprises (1) a
non-gaseous ethylenic unsaturated compound which has at least two
ethylenic unsaturated groups and forms a polymer by the aid of a
photopolymerization initiator, (2) a thermoplastic organic polymer
binder, (3) a photopolymerization initiator which is activated by
activating light, and (4) an adhesion improving additive with
respect to a metal surface, the adhesion improving additive being a
derivative of a thiohydrazide as represented by formula (I) or at
least one derivative of a carbothio acid amide as represented by
formula (II) or formula (III): ##STR3## wherein R.sub.1, R.sub.2
and R.sub.3 each represents a hydrogen atom, an alkyl group, an
aryl group, a heterocyclic group, an acyl group, or an aralkyl
group; and they may be the same or different from one another and
they may form a ring ##STR4## wherein R.sub.4 and R.sub.5 each
represents a hydrogen atom, an alkyl group, an aryl group, a
heterocyclic group, or an aralkyl group; and they may be the same
or different from each other, ##STR5## wherein R.sub.6 and R.sub.7
each represents the same group as defined for R.sub.4 and R.sub.5 ;
R.sub.8 represents an alkylene group, an arylene group or a
heteroarylene group; and n denotes 0 or 1,
and wherein the amount of ingredient (1) is 10 to 500 parts by
weight per 100 parts by weight of ingredient (2), the amount of
ingredient (3) is 0.1 to 20 parts by weight per 100 parts by weight
of ingredient (1), and the amount of ingredient (4) is 0.0005 to 5%
by weight based on the weight of the photopolymerizable
composition.
2. A photopolymerizable composition of claim 1, wherein a heat
polymerization inhibitor is included in an amount of 0.001 to 5
parts by weight per 100 parts by weight of ingredient (1).
3. A photopolymerizable composition as claimed in claim 1, wherein
the amount of ingredient (4) is 0.01 to 2 wt% based on the weight
of the photopolymerizable composition.
4. A photopolymerizable composition as claimed in claim 1, wherein
the thermoplastic organic polymer binder is a chlorinated
polyolefin, a polyacrylic alkyl ester, a polymethacrylic alkyl
ester, a copolymer of acrylic acid or methacrylic acid with acrylic
alkyl ester or methacrylic alkyl ester, polyacrylic acid,
polymethacrylic acid, a copolymer of acrylic alkyl ester or
methacrylic alkyl ester with at least one monomer of acrylonitrile,
vinyl chloride, vinylidene chloride, styrene and butadiene,
polyvinyl chloride, a copolymer of vinyl chloride and
acrylonitrile, polyvinylidene chloride, a copolymer of vinylidene
chloride and acrylonitrile, a copolymer of vinyl acetate and vinyl
chloride, polyacrylonitrile, a copolymer of acrylonitrile and
styrene, a copolymer of acrylonitrile, butadiene and styrene, a
copolymer of styrene and an unsaturated dibasic acid anhydride,
polyvinyl butyral, styrene butadiene rubber, chlorinated rubber,
cyclized rubber, or acetyl cellulose.
5. A photopolymerizable composition as claimed in claim 1, wherein
the thermoplastic organic polymer binder is chlorinated
polyethylene, chlorinated polypropylene, polymethyl methacrylate,
methacrylic acid-methyl methacrylate copolymer containing 5 to 50
mol% of methacrylic acid, methyl methacrylate-acrylonitrile
copolymer containing 20 to 80 mol% of methyl methycrylate, vinyl
chloride-acrylonitrile copolymer containing 20 to 80 mol% of vinyl
chloride, vinylidene chloride-acrylonitrile copolymer containing 20
to 80 mol% of vinylidene chloride or styrene-maleic anhydride
copolymer containing 40 to 60 mol% of styrene.
Description
FIELD OF THE INVENTION
The present invention relates to a photopolymerizable composition
which polymerizes and cures upon irradiation with activating light
and which is improved in adhesion to the surfaces of metals,
especially copper. More particularly, it relates to a
photopolymerizable composition which easily cures upon exposure to
light and forms a photoresist to be treated in an aqueous solution
for plating and etching.
BACKGROUND OF THE INVENTION
Printed circuit boards are produced using photoresists. According
to the dry film photoresist system disclosed in Japanese Patent
Publication No. 25231/70, a photoresist in the form of film is
laminated onto a copper-clad laminate (base), the photoresist is
exposed to the activating light through a mask having the wiring
pattern, and the unexposed parts are dissolved using an adequate
developing solution, whereby a cured image is obtained on the base.
The image is used as the resist and the copper not covered by the
resist is etched, plated, or anodized. Thus, there is obtained a
printed circuit board.
The dry film photoresist is not desirable because its adhesion to a
metal surface is weaker than that of the solution type photoresist.
This weak adhesion causes an unfavorable phenomenon during etching
or plating. For example, when the base is sprayed with an etching
solution or dipped in a plating solution, the solution infiltrates
into the interface between the resist and the base, causing the
resist to separate from the base. This leads to underetching or
underplating, which, in turn, causes the image to become blurred or
to disappear. If the adhesion problem is substantial, the desired
pattern is not obtained and the base is wasted.
In the production of printed circuit boards by the use of a dry
film resist, the resist pattern is closely attached to the base
over the entire surface in some cases. In other cases where the
base has through-holes, the resist pattern is not attached over the
entire surface. (The through-holes are holes made through the base,
with the inside surface thereof coated with a metal layer such as a
copper layer, and they electrically connect the printed circuits
formed on both sides of the base.) In such cases, it is necessary
to stretch the resist film over the opening of the hole, so that
the metal layer on the inside of the hole is protected from
etching. The resist film thus formed sticks to the base at a very
small area around the opening of the hole, and the film covering
the opening of the hole is not supported. Yet, the resist film is
required to have sufficient peel resistance against the etching
spray.
In order to improve the peel resistance, pretreatment of the metal
surface was proposed. (Japanese Patent Publication No. 5292/79
(U.S. Pat. No. 3,873,316) and Japanese Patent Laid-Open Nos.
64919/76 and 64920/76 (U.S. Pat. No. 4,233,395))
Several other methods for improving the adhesion by adding a
variety of compounds to the photosensitive resin layer were also
proposed. (Japanese Patent Publication Nos. 9177/75 (U.S. Pat. No.
3,622,334), 5292/79 (U.S. Pat. No. 3,873,316), 22481/80, 46053/82,
46054/82, 21697/82 and 40500/82, and Japanese Patent Laid-Open Nos.
64919/76, 64920/76, 63087/75, 2724/77, 702/78, 124541/78,
124594/78, 133585/79, 133586/79, 65947/80, 11904/81, 75642/81,
67844/81, 99202/81, 100803/81, 60327/82 and 62047/82)
The surface treatment in the former method requires an additional
step. Therefore, the latter method is superior in this respect; but
it is not desirable because the copper surface which is exposed
after development turns red, and this discoloration adversely
affects the subsequent etching, plating, or soldering. Moreover,
some additives interfere with the photopolymerization reaction and
have low miscibility with the photopolymerizable resin
composition.
SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to provide a
photopolymerizable composition which is free of the above-mentioned
disadvantages and is improved in adhesion to the metal surface.
More particularly, it is an object of this invention to provide a
photopolymerizable composition for forming a dry film resist for
the production of printed circuit boards.
The present inventors found that a photopolymerizable composition
is improved in adhesion with respect to a metal surface when it is
incorporated with a derivative of a thiohydrazide compound or a
derivative of a carbothio acid amide.
The objects of this invention can be achieved by a
photopolymerizable composition which comprises as main ingredients
(1) a non-gaseous ethylenic unsaturated compound which has at least
two ethylenic unsaturated groups and forms a polymer by the aid of
a photopolymerization initiator, (2) a thermoplastic organic
polymer binder, (3) a photopolymerization initiator which is
activated by activating light, and (4) at least one derivative of a
thiohydrazide compound as represented by formula (I) or at least
one derivative of a carbothio acid amide as represented by formula
(II) or formula (III). ##STR1##
In these formulae, R.sub.1, R.sub.2 and R.sub.3 each represents a
hydrogen atom, an alkyl group having preferably up to 12 carbon
atoms which may be substituted with, for example, --OR.sub.9 group
(R.sub.9 represents a hydrogen atom, an alkyl group having up to 4
carbon atoms or an aryl group having 6 to 12 carbon atoms,
hereinafter the same), --NR.sub.9 R.sub.10 group (R.sub.10
represents the same definition as R.sub.9 and they may be the same
or different from each other) or --OOCR.sub.11 group (R.sub.11
represents an alkyl group having up to 4 carbon atoms or an aryl
group having 6 to 12 carbon atoms), an aryl group which may be
substituted with, for example, an alkyl group having up to 4 carbon
atoms, an aryl group having 6 to 12 carbon atoms, --OR.sub.9 group
or --NR.sub.9 R.sub.10 group, a heterocyclic group which may be
substituted with, for example, an alkyl group having up to 4 carbon
atoms, an aryl group having 6 to 12 carbon atoms, --OR.sub.9 group
or --NR.sub.9 R.sub.10 group, an acyl group having preferably up to
6 carbon atoms or an aralkyl group having an alkyl group containing
up to 4 carbon atoms. They may be the same or different from one
another and they may form a ring, for example, a heterocyclic ring
such as thioketodihydropyridazine ring,
thioketotetrahydropyridazine ring and piperidine ring.
R.sub.4 and R.sub.5 each represents a hydrogen atom, an alkyl
group, an aryl group, a heterocyclic group or an aralkyl group all
of which have the same carbon numbers and/or the same substituents
as R.sub.1, R.sub.2 and R.sub.3 described above. They may be the
same or different from each other.
R.sub.6 and R.sub.7 each represents the same groups as defined for
R.sub.4 and R.sub.5, R.sub.8 represents an alkylene group having
preferably up to 6 carbon atoms an arylene group or a heteroarylene
group; and n represents 0 or 1.
As examples of the aryl group for R.sub.1 to R.sub.7, there are a
phenyl group and a naphthyl group. As examples of the heterocyclic
group for R.sub.1 to R.sub.7, there are a pyridine group, a
thiazole group, an oxazole group, a triazole group, a benzothiazole
group and a benzoxazole group. As examples of the aralkyl group for
R.sub.1 to R.sub.7, there are a phenethyl group and a phenylpropyl
group.
Examples of the R.sub.8 arylene group include a phenylene group and
a naphthylene group.
DETAILED DESCRIPTION OF THE INVENTION
The thiohydrazide derivative or carbothio acid amide derivative
used in this invention improves adhesion with respect to metal
surfaces without sacrificing the sensitivity for
photopolymerization. It is in this respect that the derivative of
this invention is different from conventional similar compounds
such as tetramethylthiuram disulfide disclosed in Japanese Patent
Publication No. 5292/79 (U.S. Pat. No. 3,873,316) and
diphenylcarbazone derivative disclosed in Japanese Patent
Publication No. 40500/82. These conventional compounds decrease the
sensitivity and impede the photopolymerization when added in an
amount sufficient to improve the adhesion with respect to the metal
surface.
In addition, the photopolymerizable composition of this invention
has no side effects which turn the copper surface red or discolor
the dye and has good solubility.
The examples of the thiohydrazide derivatives used in this
invention are represented by the following formulae 1 to 18, and
the examples of the carbothio acid amide derivatives used in this
invention are represented by the following formulae 19 to 43. The
present invention is not limited to them. ##STR2##
These compounds can be used individually or in combination with one
another. They are added in an amount of 0.0005 to 5 wt%, preferably
0.001 to 2 wt%, based on the weight of the photopolymerizable
composition.
Preferred ethylenic unsaturated compounds used in this invention
have at least two unsaturated groups at terminals and
photopolymerize upon exposure to activating light. These compounds
are referred to as "functional monomers" hereinafter.
Examples of functional monomers include compounds disclosed in
Japanese Patent Publication Nos. 5093/60, 14719/60 and
28727/69.
As a acrylic esters and methacrylic esters, there are polyacrylates
and polymethacrylates of polyhydric alcohols:
("Poly(meth)acrylates" as used herein cover dimers, trimers,
tetramers, etc., as well as polymers.) The polyhydric alcohols
include polyethylene glycol, polypropylene oxide, polybutylene
oxide, polycyclohexane oxide, polyethylene oxide, propylene oxide,
polystyrene oxide, polyoxetane, polytetrahydrofuran,
cyclohexanediol, xylylenediol, di(.beta.-hydroxyethoxy)benzene,
glycerin, diglycerin, neopentyl glycol, trimethylolpropane,
triethylolpropane, pentaerythritol, dipentaerythritol, sorbitan,
sorbitol, butanediol, butanetriol, 2-butene-1,4-diol,
2-n-butyl-2-ethylpropanediol, 2-butine-1,4-diol,
3-chloro-1,2-propanediol, 1,4-cyclohexanedimethanol,
3-cyclohexene-1,1-dimethanol, decalindiol,
2,3-dibromo-2-butene-1,4-diol, 2,2-diethyl-1,3-propanediol,
1,5-dihydroxy-1,2,3,4-tetrahydronaphthalene,
2,5-dimethyl-2,5-hexanediol, 2,2-dimethyl-1,3-propanediol,
2,2-diphenyl-1,3-propanediol, dodecanediol, mesoerythritol,
2-ethyl-1,3-hexanediol, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol,
2-ethyl-2-methyl-1,3-propanediol, heptanediol, hexanediol,
3-hexene-2,5-diol, hydroxybenzyl alcohol, hydroxyethyl resorcinol,
2-methyl-1,4-butanediol, 2-methyl-2,4-pentanediol, nonanediol,
octanediol, pentanediol, 1-phenyl-1,2-ethanediol, propanediol,
2,2,4,4-tetramethyl-1,3-cyclobutanediol,
2,3,5,6-tetramethyl-p-xylene-.alpha.,.alpha.'-diol,
1,1,4,4-tetraphenyl-1,4-butanediol,
1,1,4,4-tetraphenyl-2-butine-1,4-diol, 1,2,6-trihydroxyhexane,
1,1'-bi-2-naphthol, dihydroxynaphthalene,
1,1'-methylene-2-naphthol, 1,2,4-benzenetriol, biphenyl,
2,2'-bis(4-hydroxyphenyl)butane,
1,1-bis(4-hydroxyphenyl)cyclohexane, bis(hydroxyphenyl)methane,
catechol, 4-chlororesorcinol, 3,4-dihydroxyhydrocinnamic acid,
hydroquinone, hydroxybenzyl alcohol, methylhydroquinone,
methyl-2,4,6-trihydroxybenzoate, fluoroglucinol, pyrogallol,
resorcinol, glucose, .alpha.-(1-aminoethyl)-p-hydroxybenzyl
alcohol, 2-amino-2-ethyl-1,3-propanediol,
2-amino-2-methyl-1,3-propanediol, 3-amino-1,2-propanediol,
N-(3-aminopropyl)diethanolamine,
N,N'-bis(2-hydroxyethyl)piperazine,
2,2-bis(hydroxymethyl)-2,2',2"-nitrilotriethanol,
2,2-bis(hydroxymethyl)propionic acid, 1,3-bis(hydroxymethyl)urea,
1,2-bis(4-pyridyl)-1,2-ethanediol, N-n-butyldiethanolamine,
diethanolamine, N-ethylenediethanolamine,
3-mercapto-1,2-propanediol, 3-piperazino-1,2-propanediol,
2-(2-pyridyl)-1,3-propanediol, triethanolamine,
.alpha.-(1-aminoethyl)-p-hydroxybenzyl alcohol and
3-amino-4-hydroxyphenyl sulfone. Preferable from the standpoint of
availability among these acrylic esters and methacrylic esters are
ethylene glycol diacrylate, diethylene glycol dimethacrylate,
polyethylene glycol diacrylate, trimethylolpropane triacrylate,
trimethylolpropane trimethacrylate, pentaerythritol triacrylate,
pentaerythritol tetraacrylate, pentaerythritol dimethacrylate,
dipentaerythritol pentaacrylate, glycerin triacrylate, diglycerin
dimethacrylate, 1,3-propanediol diacrylate, 1,2,4-butanetriol
trimethacrylate, 1,4-cyclohexanediol diacrylate, 1,5-pentanediol
diacrylate, neopentyl glycol diacrylate, and triacrylic ester of
ethylene oxide adduct of trimethylolpropane.
The acrylamides and methacrylamides include not only methylene
bisacrylamide and methylene bismethacrylamide but polyacrylamide
and polymethacrylamide both derived from ethylenediamine,
diaminopropane, diaminobutane, pentamethylenediamine,
hexamethylene-bis(2-aminopropyl)amine, diethylenetriamine,
heptamethylenediamine, octamethylenediamine, polyamines having
heterogeneous atoms between two or more amino groups, and
polyamines having a ring (e.g., phenylenediamine, xylylenediamine,
.beta.-(4-aminophenyl)ethylamine, diaminobenzoic acid,
diaminotoluene, diaminoanthraquinone, and diaminofluorene).
The allyl compounds include diallyl esters of dicarboxylic acids
such as phthalic acid, terephthalic acid, sebacic acid, adipic
acid, glutaric acid, malonic acid, and oxalic acid. Examples of
such allyl esters include diallyl esters and diallyl amides of
disulfonic acids such as anthraquinone disulfonic acid, benzene
disulfonic acid, 2,5-dihydroxy-p-benzenedisulfonic acid,
dihydroxynaphthalene disulfonic acid, and naphthalenedisulfonic
acid.
The vinyl ether compounds include polyvinyl ethers of the
above-mentioned polyhydric alcohol, e.g., ethylene glycol
divinylether, 1,3,5-tri-.beta.-vinyloxyethoxybenzene,
1,3-di-.beta.-vinyloxyethoxybenzene, and glycerol trivinyl
ether.
The vinyl esters include divinyl succinate, divinyl adipate,
divinyl phthalate, divinyl terephthalate, divinyl
benzene-1,3-disulfonate, and divinylbutane-1,4-disulfonate.
Styrene compounds include divinyl benzene, p-allylstyrene, and
p-isopropenestyrene.
Those compounds which have two or more different kinds of
unsaturated bonds which undergo addition polymerization can be
suitably used in this invention. Examples of such compounds include
N-.beta.-hydroxyethyl-.beta.-(methacrylamide)ethylacrylate,
N,N-bis(.beta.-methacryloxyethyl)acrylamide, and allyl
methacrylate.
Other compounds which can be suitably used in this invention
include polyfunctional urethane compounds having at least two
ethylenic unsaturated groups. Such compounds are obtained by
reacting a reaction product of a polyol compound having at least
two hydroxyl groups and a polyisocyanate compound having at least
two isocyanate groups in a slight excess, with a compound having at
least one hydroxyl group and at least one ethylenic unsaturated
group.
These polyfunctional monomers may be used individually or in
combination with one another. They are used in an amount of 10 to
500 parts by weight, and preferably 30 to 200 parts by weight, per
100 parts by weight of the binder polymer compound.
The binder used in the photopolymerizable compound of this
invention is selected from a large variety of synthetic,
semisynthetic and natural polymeric substances which meet the
following conditions. The miscibility with the polyfunctional
monomer, photopolymerization initiator, and the thiohydrazide
compound or the carbothio acid amide compound is good to such an
extent that the binder does not separate from a coating solution
containing the above-described components in the production
processes from the preparation of the solution to the application
of the solution and subsequent drying. The binder should have
proper strength, stretchability, abrasion resistance, chemical
resistance, molecular weight, hardness, softening point,
crystallinity, and elongation at break. Examples of the binder
include chlorinated polyolefins such as chlorinated polyethylene
and chlorinated polypropylene; polyacrylic alkyl esters and
polymethacrylic alkyl esters (the alkyl group may be a methyl
group, an ethyl group, a butyl group, etc.) such as polymethyl
methacrylate; copolymers of acrylic acid or methacrylic acid with
acrylic alkyl ester or methacrylic alkyl ester (the alkyl group is
the same as above); polyacrylic acid; polymethacrylic acid;
copolymers of acrylic alkyl ester or methacrylic alkyl ester (the
alkyl group is the same as above) with at least one monomer of
acrylonitrile, vinyl chloride, vinylidene chloride, styrene, and
butadiene; polyvinyl chloride; copolymers of vinyl chloride and
acrylonitrile; polyvinylidene chloride; copolymers of vinylidene
chloride and acrylonitrile; copolymers of vinyl acetate and vinyl
chloride; polyacrylonitrile; copolymers of acrylonitrile and
styrene; copolymers of acrylonitrile, butadiene, and styrene;
copolymers of styrene and unsaturated dibasic acid anhydride such
as maleic anhydride; polyvinyl butyral; styrene butadiene rubber;
chlorinated rubber; cyclized rubber; and acetyl cellulose. The
copolymers should preferably contain more than 5 mol% of comonomer.
Any other polymers than above may be used as the binder so long as
they meet the above-mentioned conditions.
Preferable among the above-mentioned binder polymers are
chlorinated polyethylene, chlorinated polypropylene, polymethyl
methacrylate, methacrylic acid-methyl methacrylate copolymer
(containing 5 to 50 mol% of methacrylic acid), methyl
methacrylate-acrylonitrile copolymer (containing 20 to 80 mol% of
methyl methacrylate), vinyl chloride-acrylonitrile copolymer
(containing 20 to 80 mol% of vinyl chloride), vinylidene
chloride-acrylonitrile copolymer (containing 20 to 80 mol% of
vinylidene chloride), and styrene-maleic anhydride copolymer
(containing 40 to 60 mol% of styrene).
These polymers may be used individually or in combination with one
another so long as they are properly miscible with one another.
The polymer used as the binder should have a molecular weight of
5,000 to 2,000,000, and preferably 50,000 to 1,000,000.
The photopolymerization initiator used in this invention includes
the known carbonyl compounds, organic sulfur compounds, peroxides,
redox compounds, azo and diazo compounds, halogen compounds, and
photoreducing dyes as described in Chapter 5 of Light-Sensitive
Systems written by J. Causer.
Examples of carbonyl compounds include benzoin, benzoin methyl
ether, benzophenone, Michler's ketone,
4,4-bis(diethylamino)benzophenone, anthraquinone,
2-t-butylanthraquinone, 3-chlorobenzanthrone, diacetyl,
2-benzoylmethylene-3-methyl-.beta.-naphthothiazoline, and
5-chloro-3-ethyl-2-p-methoxybenzoyl methylenebenzothiazoline.
Examples of organic sulfur compounds include di-n-butyldisulfide,
dibenzyldisulfide, 2-mercaptobenzothiazole,
2-mercaptobenzimidazole, thiophenol and
ethyltrichloromethanesulfonate.
Examples of peroxides include di-t-butyl peroxide, benzoyl peroxide
and methyl ethyl ketone peroxide.
The redox compound is composed of a peroxide and a reducing agent.
Examples of redox compounds include one composed of ferrous ions
and persulfate ions and one composed of ferric ions and
peroxide.
Examples of azo and diazo compounds include
.alpha.,.alpha.'-azobisisobutyronitrile,
2-azobis-2-methylbutyronitrile, and diazonium salt of
p-aminodiphenylamine.
Examples of halogen compounds include chloromethyl naphthyl
chloride, phenacyl chloride, chloroacetone, naphthalene sulfonyl
chloride, phenyltribromomethyl sulfone, and
tris(trichloromethyl)-s-triazine.
Examples of photoreducing dyes include rose bengal, erythrosine,
eosine, acriflavine, riboflavin, and thionine.
These photopolymerization initiators may be used individually or in
combination with one another. They are used in an amount of 0.1 to
20 parts by weight, and preferably 0.5 to 10 parts by weight, per
100 parts by weight of the polyfunctional monomer.
The photopolymerizable composition of this invention should
preferably be incorporated with a heat polymerization inhibitor
such as p-methoxyphenol, hydroquinone, alkyl- or aryl-substituted
hydroquinone such as methyl-, ethyl-, propyl-, isopropyl-,
t-butyl-, phenyl- and tolyl-substituted hydroquinone,
t-butylcatechol, pyrogallol, cuprous chloride, chloranil,
naphthylamine, .beta.-naphthol, 2,6-di-t-butyl-p-cresol, pyridine,
nitrobenzene, dinitrobenzene, p-toluidine, methylene blue, organic
copper, and methyl salicylate. These inhibitors should be added in
an amount of 0.001 to 5 parts by weight per 100 parts by weight of
the polyfunctional monomer.
The photopolymerizable composition of this invention may be
incorporated with a plasticizer to properly control the film
properties. Examples of plasticizers include phthalic esters such
as dimethyl phthalate, diethyl phthalate, dibutyl phthalate,
diisobutyl phthalate, dioctyl phthalate, octylcapryl phthalate,
dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl
phthalate, diisodecyl phthalate and diaryl phthalate; glycol esters
such as dimethyl glycol phthalate, ethylphthalyl ethylglycolate,
methyl phthalyl ethylglycolate, butylphthalyl butylglycolate and
triethylene glycol dicaprylic ester; phosphoric esters such as
tricresyl phosphate and triphenyl phosphate; esters of dibasic
fatty acids such as diisobutyl adipate, dioctyl adipate, dimethyl
sebacate, dibutyl sebacate, dioctyl sebacate and dibutyl maleate;
amides such as benzenesulfonamide, p-toluenesulfonamide and
N-n-butylacetamide; and triethyl citrate, glycerin triacetyl ester
and butyl laurate.
When in use as an image forming material, the photopolymerizable
composition of this invention is dissolved or dispersed in a
solvent, and the resulting solution is applied to a support by a
proper method, the applied solution is dried, and, if necessary,
the dried film is covered with a protective film.
The solvent includes, for example ketones such as acetone, methyl
ethyl ketone, methyl isobutyl ketone, cyclohexanone and diisobutyl
ketone; esters such as ethyl acetate, butyl acetate, n-amyl
acetate, methyl formate, ethyl propionate, dimethyl phthalate and
ethyl benzoate; aromatic hydrocarbons such as toluene, xylene,
benzene and ethylbenzene; halogenated hydrocarbons such as carbon
tetrachloride, trichloroethylene, chloroform,
1,1,1-trichloroethane, methylene chloride and monochlorobenzene;
ethers such as tetrahydrofuran, diethyl ether, ethylene glycol
monomethyl ether and ethylene glycol monoethyl ether; and
dimethylformamide and dimethyl sulfoxide.
The above-mentioned support should be transparent to light and have
a uniform surface. The support is comprised of plastic films
comprised of polyethylene terephthalate, polypropylene,
polyethylene, cellulose triacetate, cellulose diacetate, polyalkyl
acrylate (the alkyl group is a methyl group, an ethyl group, a
butyl group, etc. hereinafter the same), polyalkyl methacrylate,
alkyl acrylate copolymer and alkyl methacrylate copolymer,
polyvinyl chloride, polyvinyl alcohol, polycarbonate, polystyrene,
cellophane, polyvinylidene chloride copolymer, polyamide,
polyimide, vinyl chloride-vinyl acetate copolymer,
polytetrafluoroethylene, polytrifluoroethylene, and others. The
support may be made of a composite material thereof. The support is
5 to 150 .mu.m thick, and preferably 10 to 50 .mu.m thick.
The photopolymerizable composition is formed on the support in a
dry thickness of 5 to 100 .mu.m, and preferably 10 to 80 .mu.m,
depending on the required performance of the image.
The photopolymerizable composition of this invention is applied to
the support, and, as occasion demands, the layer of the
photopolymerizable composition may be covered with a protective
film. Such a protective film may be selected from the
above-mentioned plastic films used for the support, paper, and
polyethylene- or polypropylene-laminated paper. The protective film
should be 5 to 100 .mu.m thick, and preferably 10 to 50 .mu.m
thick. The bond strength between the photopolymerizable composition
layer and the support should be greater than that between the
photopolymerizable composition layer and the protective layer.
Examples of the combination of the support and protective film
include polyethylene terephthalate/polypropylene, polyethylene
terephthalate/polyethylene, polyamide (nylon 6)/polyethylene,
polyvinyl chloride/cellophane, and polyimide/polypropylene.
The proper bond strength is obtained by selecting the support and
protective film which are different kinds of compounds from each
other as mentioned above, or by surface-treating at least either of
the support or the protective film. The surface treatment of the
support is carried out to increase the bond strength between the
support and the photopolymerizable composition layer. Examples of
the surface treatment include undercoating, corona discharge
treatment, flame treatment, UV irradiation, high-frequency
irradiation, glow discharge treatment, active plasma treatment and
laser irradiation.
The surface treatment of the protective film is usually carried out
to lower the bond strength between the photopolymerizable layer and
the protective film. Examples of such surface treatment include
undercoating with polyorganosiloxane, fluorinated polyolefin, or
polyfluoroethylene. The undercoating is usually dried at 30.degree.
to 150.degree. C., preferably 50.degree. to 120.degree. C., for 1
to 30 minutes.
When the image forming material is covered with a protective film,
the protective film is peeled off so that the photopolymerizable
layer is exposed, before the image forming material is laminated
under pressure onto a clean base surface.
A variety of bases are used according to the object for which this
invention is intended. Examples of the bases include plastic film,
paper, wood, metal plate, and glass plate. When this invention is
used as a resist to make printed circuits, the base is a printed
circuit board base which is a plastic plate laminated with a thin
metal (copper, aluminum, silver, etc.) layer or a plastic film
having a thin metal layer formed thereon by plating or vacuum
deposition. When the invention is used for making a printing plate,
the base is an aluminum plate or a plastic film having an aluminum
layer formed thereon. In such a case, the aluminum surface should
preferably be silicate-treated or anodized.
The photopolymerizable composition layer should be laminated onto
the base at room temperature (15.degree. to 30.degree. C.) or with
heating (30.degree. to 180.degree. C.), and preferably at
80.degree. to 140.degree. C.
The photosensitive layer laminated onto the base is exposed through
the transparent support to light passing through a mask. Examples
of useful light sources include a high-pressure mercury vapor lamp,
xenon lamp, carbon arc lamp, halogen lamp, or fluorescent lamp,
which radiates electromagnetic waves which pass through the
transparent support and activate the photopolymerization initiator.
The wavelength ranges from 310 to 700 nm, and preferably 350 to 500
nm, or ultraviolet rays to visible rays. The exposure may also be
accomplished by using laser, electron rays, or X-rays.
After the exposure of a desired pattern, the unexposed parts are
dissolved by a developing solution such as an organic solvent,
aqueous alkaline solution, or aqueous alkaline solution containing
an organic solvent. Thus, there is obtained a photocured image on
the base.
After the image formation, the base undergoes a subsequent
treatment, if necessary. For example, in the production of printed
circuit boards, the base undergoes etching with an etching solution
of copper chloride or ferric chloride so that the exposed metal is
removed, or the base undergoes plating with a plating solution of
copper pyrophosphate or copper sulfate so that the exposed metal is
plated.
The photopolymerizable resin composition of this invention is
suitably used for the production of printed circuit boards. It is
also used for the production of lithographic plates, letterpress
plates, reliefs, optical duplicates and photography.
The invention is described in more detail with reference to the
following non-limiting examples. "Percent" in the examples means
"percent by weight".
EXAMPLE 1
Photopolymerizable compositions of the following formulation were
prepared. The identification and quantity of the thiohydrazide
compound are shown in Table 1. The resulting composition was
dissolved in 45 g of methyl ethyl ketone to prepare an application
solution.
______________________________________ Polymethyl methacrylate
[average 15.0 g molecular weight (weight-average): 140,000]
Tetraethylene glycol diacrylate 6.1 g Trimethylolpropane
triacrylate 2.4 g p-Toluenesulfonamide 1.62 g p-Methoxyphenol 0.01
g Malachite green 0.015 g 4,4'-Bis(diethylamino)benzophenone 0.04 g
Benzophenone 0.15 g Phenyltribromomethylsulfone 0.37 g
Thiohydrazide compound See Table 1
______________________________________
The application solution was applied to a 25 .mu.m thick
polyethylene terephthalate support, followed by drying at
100.degree. C. for 2 minutes. There was obtained an approximately
50 .mu.m thick coating film. The resulting photosensitive material
was laminated onto a cleaned copper-clad laminate board (base) at
120.degree. C. Then, the photosensitive material was exposed for 10
seconds to light radiated from a 2 kw high-pressure mercury vapor
lamp (Jet Light produced by Oak Co., Ltd.) placed 50 cm away. The
temporary support was stripped off from the exposed photosensitive
material.
The adhesion of the cured film to the base was evaluated by the
crosscut test. (Eleven parallel scratches, 1 mm apart, were made
through the film, and then second eleven parallel scratches, 1 mm
apart, were made at right angles to the first scratches. Polyester
pressure-sensitive tape was pressed down over the cross-cut area
and jerked away. The number of small squares remaining is a measure
of adhesion.) The results are shown in Table 1.
It is noted from Table 1 that each of the thiohydrazide compounds
remarkably increases the adhesion.
TABLE 1 ______________________________________ Quantity Crosscut
Thiohydrazide Added Test Compound (mg) (%) Remarks
______________________________________ -- -- 20 Comparison Compound
1 6.6 90 The present invention Compound 3 11.1 95 The present
invention Compound 6 16.7 97 The present invention Compound 7 17.7
96 The present invention Compound 9 8.2 95 The present invention
Compound 11 11.9 100 The present invention Compound 12 17.4 100 The
present invention Compound 13 11.9 98 The present invention
Compound 14 12.3 99 The present invention Compound 15 11.1 95 The
present invention Compound 16 12.3 97 The present invention
Compound 18 11.9 100 The present invention
______________________________________
EXAMPLE 2
Example 1 was repeated except that the thiohydrazide compounds were
replaced by the carbothio acid amide compounds as shown in Table 2.
The results are also shown in Table 2.
It is noted from Table 2 that each of the carbothio acid amide
compounds remarkably increases the adhesion.
TABLE 2 ______________________________________ Quantity Crosscut
Carbothio Acid Added Test Amide Compound (mg) (%) Remarks
______________________________________ -- -- 20 Comparison Compound
19 5.5 95 The present invention Compound 20 6.5 90 The present
invention Compound 22 10.0 99 The present invention Compound 27 7.7
92 The present invention Compound 28 11.6 100 The present invention
Compound 31 6.5 97 The present invention Compound 32 11.0 98 The
present invention Compound 35 15.5 95 The present invention
Compound 36 14.0 100 The present invention Compound 38 8.8 100 The
present invention Compound 39 10.8 100 The present invention
______________________________________
EXAMPLE 3
The photosensitive material was obtained in the same way as in
Example 1. It was laminated at 120.degree. C. onto both sides of a
cleaned copper-clad (both sides) laminate board (base) having 500
through-holes, 1.5 mm in diameter. Then, the photosensitive
material was exposed for 10 seconds to light radiated from a 2 kw
high-pressure mercury vapor lamp (Jet Light produced by Oak Co.,
Ltd.) placed 50 cm away, with a wiring pattern mask in close
contact with the temporary support. The mask has 0.3 to 2.0 mm wide
wiring patterns and also has circular patterns 2.5 mm in diameter
which cover individual through-holes. The temporary support was
stripped off from the exposed photosensitive material. The
unexposed parts were dissolved by spraying 1,1,1-trichloroethane
for 60 seconds, followed by washing with water and drying. Thus,
there were obtained images of wiring patterns.
The copper base having resist patterns thereon was subjected to
spray etching with 42.degree. Be ferric chloride aqueous solution
at 40.degree. C. The resist film formed on the copper layer did not
peel during the etching in all the cases. The resist film was
formed on almost all the openings of the through-holes as shown in
Table 3. In the ratio of resist film formed on through-holes shown
in Table 3, 100% means that the resist film is formed on all of the
openings of the through-holes (that is, 500 openings).
The thiohydrazide compound and the quantity added are also shown in
Table 3. It is noted from Table 3 that the photosensitive material
containing a thiohydrazide compound forms the resist film on the
openings of the through-holes at a very high ratio.
TABLE 3 ______________________________________ Ratio of Resist
Quantity Film Formed on Thiohydrazide Added Through-Holes Compound
(mg) (%) Remarks ______________________________________ -- -- 30
Comparison Compound 1 6.6 96 The present invention Compound 3 11.1
98 The present invention Compound 6 16.7 99 The present invention
Compound 7 17.7 98 The present invention Compound 9 8.2 97 The
present invention Compound 11 11.9 100 The present invention
Compound 12 17.4 100 The present invention Compound 13 11.9 99 The
present invention Compound 14 12.3 100 The present invention
Compound 15 11.1 98 The present invention Compound 16 12.3 99 The
present invention Compound 18 11.9 100 The present invention
______________________________________
EXAMPLE 4
By using the sensitive material obtained in Example 2, an image of
a wiring pattern was obtained in the same way as in Example 3. The
copper base having the resist pattern thereon was subjected to
spray etching with 42.degree. Be ferric chloride aqueous solution
at 40.degree. C. The resist film formed on the copper layer did not
peel during the etching in all the cases. The resist film was
formed on almost all the openings of the through-holes as shown in
Table 4.
TABLE 4 ______________________________________ Ratio of Resist
Quantity Film Formed on Carbothio Acid Added Through-Holes Amide
Compound (mg) (%) Remarks ______________________________________ --
-- 30 Comparison Compound 19 5.5 98 The present invention Compound
20 6.5 97 The present invention Compound 22 10.0 100 The present
invention Compound 27 7.7 96 The present invention Compound 28 11.6
100 The present invention Compound 31 6.5 98 The present invention
Compound 32 11.0 99 The present invention Compound 35 15.5 97 The
present invention Compound 36 14.0 100 The present invention
Compound 38 8.8 100 The present invention Compound 39 10.8 100 The
present invention ______________________________________
EXAMPLE 5
The sensitive material was obtained in the same manner as in
Example 1 except that 4,4'-bis(diethylamino)benzophenone,
benzophenone and phenyltribromomethylsulfone were replaced by 0.19
g of 3-chlorobenzanthrone and 0.19 g of Michler's ketone. The
resulting sensitive material was laminated onto a cleaned
copper-clad laminate board at 120.degree. C. Exposure was performed
in the same manner as in Example 1. The temporary support was
peeled away. An epoxy adhesive was applied to the cured resist
surface. A copper-clad board was bonded th the epoxy adhesive. The
shear peel strength of the laminated resist layer was measured. The
results are shown in Table 5. The identification of thiohydrazide
compounds and the quantity added are also shown in Table 5. It is
noted from Table 5 that the sensitive material containing a
thiohydrazide compound of this invention is high in shear
strength.
TABLE 5 ______________________________________ Quantity Shear Peel
Thiohydrazide Added Strength Compound (mg) (kg/cm.sup.2) Remarks
______________________________________ -- -- 10.5 Comparison
Compound 1 6.6 32.0 The present invention Compound 3 11.1 35.0 The
present invention Compound 6 16.7 35.5 The present invention
Compound 11 11.9 37.0 The present invention Compound 12 17.4 36.5
The present invention ______________________________________
EXAMPLE 6
The sensitive material was obtained in the same manner as in
Example 2 except that 4,4'-bis(diethylamino)benzophenone,
benzophenone and phenyltribromomethylsulfone were replaced by 0.19
g of 3-chlorobenzanthrone and 0.19 g of Michler's ketone. The
resulting sensitive material was laminated onto a cleaned
copper-clad laminate board at 120.degree. C. Exposure was performed
in the same manner as in Example 2. The temporary support was
peeled away. An epoxy adhesive was applied to the cured resist
surface. A copper-clad board was bonded to the epoxy adhesive. The
shear peel strength of the laminated resist layer was measured. The
results are shown in Table 6. The identification of carbothio acid
amide compounds and the quantity added are also shown in Table 6.
It is noted from Table 6 that the sensitive material containing a
carbothio acid amide compound of this invention is high in shear
strength.
TABLE 6 ______________________________________ Quantity Shear Peel
Carbothio Acid Added Strength Amide Compound (mg) (kg/cm.sup.2)
Remarks ______________________________________ -- -- 10.5
Comparison Compound 19 5.5 35.0 The present invention Compound 20
6.5 33.5 The present invention Compound 22 10.0 37.0 The present
invention Compound 36 14.0 36.5 The present invention Compound 38
8.8 37.0 The present invention
______________________________________
EXAMPLE 7
The sensitive materials were prepared in the same manner as in
Example 1 using the following thiohydrazide compounds.
______________________________________ Compound 3 11.1 mg Compound
6 16.7 mg Compound 11 11.9 mg Compound 12 17.4 mg
______________________________________
The resulting sensitive material was laminated onto a copper-clad
board. Exposure, development and washing were performed in the same
manner as in Example 3. Thus, there was obtained a copper-clad base
having a cured resist pattern thereon. The exposed copper was
plated with solder by using a borofluoride bath of the following
composition.
______________________________________ Tin borofluoride
Sn(BF.sub.4).sub.2 (45% aq. soln.) 300 g Lead borofluoride
Pb(BF.sub.4).sub.2 (45% aq. soln.) 100 g Borofluoric acid HBF.sub.4
(42% aq. soln.) 200 g Boric acid H.sub.3 BO.sub.3 28 g Water q.s.
to 1 l ______________________________________
Plating Conditions
Anode: solder rod (tin/lead=6:4)
Bath temperature: 30.degree. C.
Current density of cathode: 3.0 A/dm.sup.2
Time: 30 minutes
Plating was successfully performed without peeling of resist
pattern or the occurrence of pinholes. The resist was easily
removed by spraying methylene chloride thereon. The exposed copper
was etched by a 20% aqueous solution of ammonium persulfate. Thus,
there was obtained a clear wiring pattern.
EXAMPLE 8
The sensitive materials were prepared in the same manner as in
Example 1 using the following carbothio acid amide compounds.
______________________________________ Compound 19 thioacetamide
5.5 mg Compound 22 thiobenzamide 10.0 mg Compound 32
thioacetanilide 11.0 mg Compound 38 dithiooxamide 8.8 mg
______________________________________
The resulting sensitive material was laminated onto a copper-clad
board in the same manner as in Example 1. Exposure, development and
washing were performed in the same manner as in Example 3. Thus,
there was obtained a copper-clad base having a cured resist pattern
thereon. The exposed copper was plated with solder in the same
manner as in Example 7. Plating was successfully performed without
peeling of the resist pattern or the occurrence of pinholes. The
resist was easily removed by spraying methylene chloride thereon.
The exposed copper was etched by a 20% aqueous solution of ammonium
persulfate. Thus, there was obtained a clear wiring pattern.
EXAMPLE 9
The sensitive materials were prepared in the same manner as in
Example 1. Compound 6 and Compound 11 were used as the
thiohydrazide compound. For comparison, the sensitive material was
prepared in which the thiohydrazide was replaced by
tetramethylthiuramdisulfide and diphenylthiocarbazone. The
resulting sensitive material was laminated onto a cleaned copper
plate in the same manner as in Example 1. The same crosscut test as
in Example 1 was carried out.
On the other hand, the sensitive material was exposed in the same
manner as in Example 3, with a step wedge (a density increase of
0.15 (.DELTA. log E) at each step) in close contact with the
temporary support. After development, washing and drying, there was
obtained a negative image corresponding to the wedge. The
sensitivity of the sensitive material was evaluated by the step of
density at which the image was completely dissolved. The
sensitivity of the sensitive material containing Compound 6 was
regarded as 100, and the sensitivity of the other sensitive
materials was comparatively determined. The results are shown in
Table 7.
TABLE 7 ______________________________________ Cross- Quantity cut
Compound Added Test Comparative Used (mg) (%) Sensitivity Remarks
______________________________________ Compound 6 16.7 97 100 The
present invention Compound 11 11.9 100 100 The present invention
Tetramethyl- 18.7 90 40 Comparison thiuramdisulfide Diphenylthio-
17.5 95 30 Comparison carbazone
______________________________________
It is noted from Table 7 that the thiohydrazide compounds of the
present invention remarkably increase the sensitivity are compared
with the other compounds.
EXAMPLE 10
The sensitive materials were prepared in the same manner as in
Example 1. Compound 19 and Compound 22 were used as the carbothio
acid amide compound. For comparison, the sensitive material was
prepared in which the carbothio acid amide compound was replaced by
tetramethylthiuramdisulfide and diphenylcarbazone. The resulting
sensitive material was laminated onto a cleaned copper plate in the
same manner as in Example 1. The same crosscut test as in Example 1
was carried out.
On the other hand, the sensitive material was exposed in the same
manner as in Example 3, with a step wedge (a density increase of
0.15 (.DELTA. log E) at each step) in close contact with the
temporary support. After development, washing and drying, there was
obtained a negative image corresponding to the wedge. The
sensitivity of the sensitive material was evaluated by the step of
the wedge at which the image was completely dissolved. The
sensitivity of the sensitive material containing Compound 19 was
regarded as 100, and the sensitivity of the other sensitive
materials was comparatively determined. The results are shown in
Table 8.
TABLE 8 ______________________________________ Cross- Quantity cut
Compound Added Test Comparative Used (mg) (%) Sensitivity Remarks
______________________________________ Compound 19 5.5 95 100 The
present invention Compound 22 10.0 99 100 The present invention
Tetramethyl- 18.7 90 40 Comparison thiuramdisulfide Diphenylthio-
17.5 95 30 Comparison carbazone
______________________________________
It is noted from Table 8 that the carbothio acid amide compounds of
the present invention remarkably increase the sensitivity as
compared with the other compounds.
While the invention has been described in detail and with reference
to specific embodiments thereof, it will be apparent to one skilled
in the art that various changes and modifications can be made
therein without departing from the spirit and scope thereof.
* * * * *